LXR uboot/include/binman

   1/* SPDX-License-Identifier: GPL-2.0+ */
   2/*
   3 * Symbol access for symbols set up by binman as part of the build.
   4 *
   5 * This allows C code to access the position of a particular part of the image
   6 * assembled by binman.
   7 *
   8 * Copyright (c) 2017 Google, Inc
   9 */
  10
  11#ifndef __BINMAN_SYM_H
  12#define __BINMAN_SYM_H
  13
  14/* BSYM in little endian, keep in sync with tools/binman/elf.py */
  15#define BINMAN_SYM_MAGIC_VALUE  (0x4d595342UL)
  16#define BINMAN_SYM_MISSING      (-1UL)
  17
  18#if CONFIG_IS_ENABLED(BINMAN_SYMBOLS)
  19
  20/**
  21 * binman_symname() - Internal function to get a binman symbol name
  22 *
  23 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
  24 * @_prop_name: Property value to get from that entry (e.g. 'pos')
  25 * @returns name of the symbol for that entry and property
  26 */
  27#define binman_symname(_entry_name, _prop_name) \
  28        _binman_ ## _entry_name ## _prop_ ## _prop_name
  29
  30/**
  31 * binman_sym_declare() - Declare a symbol that will be used at run-time
  32 *
  33 * @_type: Type f the symbol (e.g. unsigned long)
  34 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
  35 * @_prop_name: Property value to get from that entry (e.g. 'pos')
  36 */
  37#define binman_sym_declare(_type, _entry_name, _prop_name) \
  38        _type binman_symname(_entry_name, _prop_name) \
  39                __attribute__((aligned(4), unused, section(".binman_sym")))
  40
  41/**
  42 * binman_sym_extern() - Declare a extern symbol that will be used at run-time
  43 *
  44 * @_type: Type f the symbol (e.g. unsigned long)
  45 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
  46 * @_prop_name: Property value to get from that entry (e.g. 'pos')
  47 */
  48#define binman_sym_extern(_type, _entry_name, _prop_name) \
  49        extern _type binman_symname(_entry_name, _prop_name) \
  50                __attribute__((aligned(4), unused, section(".binman_sym")))
  51
  52/**
  53 * binman_sym_declare_optional() - Declare an optional symbol
  54 *
  55 * If this symbol cannot be provided by binman, an error will not be generated.
  56 * Instead the image will be assigned the value BINMAN_SYM_MISSING.
  57 *
  58 * @_type: Type f the symbol (e.g. unsigned long)
  59 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
  60 * @_prop_name: Property value to get from that entry (e.g. 'pos')
  61 */
  62#define binman_sym_declare_optional(_type, _entry_name, _prop_name) \
  63        _type binman_symname(_entry_name, _prop_name) \
  64                __attribute__((aligned(4), weak, unused, \
  65                section(".binman_sym")))
  66
  67/**
  68 * _binman_sym_magic - Internal magic symbol for validity checks
  69 *
  70 * When building images, binman fills in this symbol with the magic
  71 * value #defined above. This is used to check at runtime if the
  72 * symbol values were filled in and are OK to use.
  73 */
  74extern ulong _binman_sym_magic;
  75
  76/**
  77 * DECLARE_BINMAN_MAGIC_SYM - Declare the internal magic symbol
  78 *
  79 * This macro declares the _binman_sym_magic symbol so that it exists.
  80 * Declaring it here would cause errors during linking due to multiple
  81 * definitions of the symbol.
  82 */
  83#define DECLARE_BINMAN_MAGIC_SYM \
  84        ulong _binman_sym_magic \
  85                __attribute__((aligned(4), section(".binman_sym")))
  86
  87/**
  88 * BINMAN_SYMS_OK - Check if the symbol values are valid
  89 *
  90 * This macro checks if the magic symbol's value is filled properly,
  91 * which indicates that other symbols are OK to use as well.
  92 *
  93 * Return: 1 if binman symbol values are usable, 0 if not
  94 */
  95#define BINMAN_SYMS_OK \
  96        (*(ulong *)&_binman_sym_magic == BINMAN_SYM_MAGIC_VALUE)
  97
  98/**
  99 * binman_sym() - Access a previously declared symbol
 100 *
 101 * This is used to get the value of a symbol. E.g.:
 102 *
 103 *    ulong address = binman_sym(ulong, u_boot_spl, pos);
 104 *
 105 * @_type: Type f the symbol (e.g. unsigned long)
 106 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
 107 * @_prop_name: Property value to get from that entry (e.g. 'pos')
 108 *
 109 * Return: value of that property (filled in by binman), or
 110 *         BINMAN_SYM_MISSING if the value is unavailable
 111 */
 112#define binman_sym(_type, _entry_name, _prop_name) \
 113        (BINMAN_SYMS_OK ? \
 114         (*(_type *)&binman_symname(_entry_name, _prop_name)) : \
 115         BINMAN_SYM_MISSING)
 116
 117#else /* !CONFIG_IS_ENABLED(BINMAN_SYMBOLS) */
 118
 119#define binman_sym_declare(_type, _entry_name, _prop_name)
 120
 121#define binman_sym_declare_optional(_type, _entry_name, _prop_name)
 122
 123#define binman_sym_extern(_type, _entry_name, _prop_name)
 124
 125#define DECLARE_BINMAN_MAGIC_SYM
 126
 127#define BINMAN_SYMS_OK (0)
 128
 129#define binman_sym(_type, _entry_name, _prop_name) BINMAN_SYM_MISSING
 130
 131#endif /* CONFIG_IS_ENABLED(BINMAN_SYMBOLS) */
 132
 133#endif
 134